As a network, which conforms to the SONET/SDH, a virtual concatenation (VCAT) technology is known as one of technologies to efficiently accommodate a data signal such as a Ethernet (registered trademark) signal.
According to the VCAT technology, a VCAT signal in a transmission band obtained by arbitrary multiplying the transmission band of the SONET/SDH path may be generated, by virtually concatenating arbitrary number of SONET/SDH paths. This allows to transparently transmit the signals of various data rates to the network of the SONET/SDH.
In addition, a link capacity adjustment scheme (LCAS) also is known as one of the technologies capable of hitlessly (without failure) and dynamically adjusting a size (transmission band) of a virtual concatenation group (VCG).
Meanwhile, the VCAT is defined by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) recommendation G. 707, and the LCAS is defined by the ITU-T recommendation G. 7042.    [Patent Document 1] Japanese Laid-Open Patent Application No. 2004-32061    [Non-Patent Document 1] ITU-T recommendation G.707, “Network node interface for the synchronous digital hierarchy (SDH)”, [online], January 2007, ITU-T, [searched on Apr. 7, 2008], Internet <URL: http://www.itu.int/rec/T-REC-G.707/en>    [Non-Patent Document 2] ITU-T recommendation G.7042, “Link capacity adjustment scheme (LCAS) for virtual concatenated signals”, [online], March 2006, ITU-T [searched on Apr. 7, 2008], Internet <URL: http://www.itu.int/rec/T-REC-G.7042/en>
When a failure occurs in the VCG member path, the conventional technology may only eliminate the VCG member path in which the failure occurs from the operational member by using the LCAS protocol and operate with remaining VCG member paths.
Also, when realizing path level redundancy, this may only switch between the VCG member paths fixedly set as current and backup in advance.
(1) A transmission system that virtually concatenates each path signal transmitted through a plurality of paths being a logical communication path to form a virtual concatenation group, the system including:
managing means for managing an active state and a stand-by state of member paths of the virtual concatenation group; and
control means for controlling any of the member paths in the stand-by state to the active state in place of any of the member paths in the active state that has abnormality, can be used.
(2) A path control method in a transmission system that virtually concatenates each path signal transmitted through a plurality of paths being a logical communication path to form a virtual concatenation group, the method including:
managing an active state and a stand-by state of member paths of the virtual concatenation group; and
controlling any of the member paths in the stand-by state to the active state in place of any of the member paths in the active state that has abnormality, can be used.
(3) A transmission device on a receiving side for receiving a path signal from the transmission device on a transmitting side that virtually concatenates each path signal transmitted through a plurality of paths being a logical communication path to form a virtual concatenation group, the device including:
managing means for managing an active state and a stand-by state of member paths of the virtual concatenation group; and
control means for controlling any of the member paths in the stand-by state to the active state in place of any of the member paths in the active state that has abnormality, can be used.
Additional objects and advantages of the invention(s) will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention(s). The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the embodiment, as claimed.